Minimally invasive interventions and minimally surgical interventional procedures on patients are increasingly replacing traditional surgical operations. A factor of crucial importance in this regard is good anatomical and functional medical imaging, in particular of soft tissue, in the case of interventions involving the heart and liver for example. For this purpose use is predominantly made of X-ray devices for acquiring fluoroscopic images, said devices possessing a certain mobility to enable the image acquisition means to be positioned as appropriate in order to permit the intervention that is being performed in parallel. Mobile C-arm X-ray machines are known in which a radiation source and a radiation detector are arranged at the ends of a C-arm, said C-arm having the ability to be moved in space and positioned relative to the patient or, as the case may be, the treatment region. However, X-ray machines of this kind generally provide only 2D images and sometimes the soft-tissue resolution is unsatisfactory or the image quality is not such that sufficient information can be acquired in particular in the case of complex interventions.
Improved image acquisition, including with regard to three-dimensional imaging, is possible by means of an imaging apparatus comprising a ring-shaped gantry, i.e. a mobile computed tomography (CT) scanner or a mobile computed tomography gantry which is arranged on a supporting structure such as a mobile cart which can travel across a floor for example, as described by way of example in U.S. Pat. No. 6,940,941. By means of such a mobile CT scanner, in the gantry of which there rotates a rotating rotor arrangement having an image acquisition means comprising a radiation source and, for example, a radiation detector arranged offset by 180° therefrom, i.e. disposed opposite thereto, images can be recorded continuously during the treatment owing to the continuous rotation of the rotor arrangement, thereby resulting in very good soft-tissue resolution within the acquired images, and consequently in very good image quality. Also provided in the case of the gantry known from U.S. Pat. No. 6,940,941 is a detachable or breakable gantry segment, which is to say that the gantry can be opened laterally, thus enabling the patient to be introduced into the gantry from the lateral direction.
However, a disadvantage of the known mobile gantry is to be seen in the fact that e.g. the mobile cart on which the gantry is arranged takes up a considerable amount of space which is then no longer available for positioning other equipment required for a treatment or in which it is also not possible for persons involved in the treatment to remain.
In particular in computed tomography examinations of the heart it is furthermore only possible to record an entire cardiac cycle using an image acquisition means having a rotating radiation source when the heart rate is reduced to 60 bpm or less with the aid of suitable drugs, beta blockers for example. This is disadvantageous for the patient on the one hand, and on the other hand optimal image acquisition is not always assured, especially at somewhat slower rotational speeds.